Carotid Body Tumor (CBT) is the most common tumor in the family of head and neck paragangliomas, making up approximately 60-70% of them. They are typically diagnosed in the 4th to 5th decades with a female predilection. CBT present as soft tissue density on non-contrast CT and complete transfemoral angiography is considered the "gold standard" when establishing diagnosis of carotid body tumors with a 100% accuracy. Primary treatment consists of surgical resection to reduce tumor mass size and to decrease surgical risks associated with resection of these highly vascularized tumors, preoperative embolization of CBT has been proposed in the literature with varying results. There are no universal guidelines regarding preoperative CBT embolization and performance is mostly guided by preference of the surgeon and tumor size. The decision to perform pre-operative embolization, usually 24-48 hours before surgery (though timing of surgical CBT resection following prior embolization varies between 1 to 14 days post embolization), is largely dependent on tumor size. Embolization can be done via a transfemoral arterial route, or percutaneous (direct intralesional) route. The aim of this study is to investigate the efficacy of preoperative embolization prior to surgical CBT resection regarding intraoperative blood loss, operative time, length of hospital stay, and perioperative complications (e.g. transient or ischemic cerebrovascular event, vascular injury, or cranial nerve injury).

A systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (2020) statement. All studies reporting on patients with a CBT that compare treatment with preoperative embolization prior to surgical CBT resection and treatment with surgical CBT resection alone were included. PubMed, Scopus and Web of Science were systematically searched, and selected journals were screened for articles in press. Meta-analysis was performed using a random effects model. Study heterogeneity was assessed using the I2 statistic. Quality assessment of included studies was done using the Newcastle-Ottawa Scale (NOS). Publication bias was assessed using funnel plots and Egger's regression test.

A total of 1915 studies were identified during the initial search; 951 of them were duplicates and were removed. The remaining 964 studies were screened on title and abstract for eligibility. Most of these studies were excluded for reporting data on paragangliomas other than CBT, focusing on diagnostical evaluation or genetical evaluation only or focusing on the treatment of CBT with radiotherapy instead of surgical resection with or without preoperative embolization. Finally, 21 studies in total were eligible for systematic review and 17 studies were eligible for meta-analysis. All studies reported embolization via a transfemoral arterial route. None of the studies reported experience with percutaneous embolization of CBTs. Included studies comprised 1326 patients. The preoperative embolization group comprised of 426 patients compared to 864 patients in the surgical resection without prior embolization group. We found no significant differences regarding intraoperative blood loss, operative time, and perioperative complications between both groups. The preoperative embolization group had a significant shorter length of hospital stay as compared to surgical CBT resection alone (SMD = -0.43; 95% CI: -0.79 - -0.07; P = .02).

This systematic review and meta-analysis found a significant benefit of preoperative embolization in surgical CBT resection regarding length of hospital stay. There was no difference regarding intraoperative blood loss, operative time and perioperative complications between both groups.